Japanese Patent Publication No. 2006-27476 discloses an opening/closing mechanism of a storage box that is capable of making operational property favorable involving opening and closing operation of a lid without requiring electric power. The opening/closing mechanism comprises a pivot shaft 25 disposed in the backward of a box body 13, a base panel 22 adapted to rotate around the pivot shaft 25, a lid 14 connected to the base panel 22 through a slide groove 21 and a slide pin 23 and adapted to be slidable in an anteroposterior direction of the box body 13, guide pins 19 formed on the lid 14, and guide grooves 17 formed on the sidewalls of the box body 13 to receive the guide pins 19 slidably. The guide groove 17 is comprised of a linear part and an arc-shaped part, wherein the linear part extends from an anterior end to a middle portion of the guide groove 17 with ascending moderately toward the middle portion, while the arc-shaped part extends from the middle portion to a posterior end of the guide groove 17 with rising steeply toward the posterior end. The arc-shaped part extends along a circular arc centering on the pivot shaft 25. As the lid 14 is pulled toward the backward of the box body 13, the guide pin 19 of the lid 14 moves along the guide groove 17 of the box body 13. While the guide pin 19 moves along the linear part of the guide groove 17, the base panel 22 relatively moves toward the front end of the lid 14, thereby making the distance between the front end of the lid 14 and the rotary shaft 15 short. As the guide pin 19 subsequently moves along the arc-shaped part of the guide groove 17, the lid 14 and the base panel 22 are made to rotate around the pivot shaft 25 by camming action caused between the arc-shaped part and the guide pin 19, and the box body 13 is opened. Then, the front end of the lid 14 and the pivot shaft 15 come close to each other and the front end of the lid 14 traces a circular track of smaller radius centering on the pivot shaft 25. Consequently, a vehicle driver can rotate a front end of the lid 14 along a circular arc having a reduced radius when opening and closing the lid and this improves operationality of the lid 14. In addition, it is advantageous that the biasing force for assisting closing movement of the lid 14 should be a turning force centering on the pivot shaft 25 as far as the guide pin 19 moves along the arc-shaped part of the guide groove 17 and a linear force toward the frontward of the box body as far as the guide pin 19 moves along the linear part of the guide groove 17. In order to accumulate the turning force and the linear force when opening the lid 14, the opening/closing mechanism comprises two independent accumulation mechanisms for storing these biasing forces. The first accumulation mechanism is composed of a drum 26 and a constant load spring 27 in order to store the linear force while the lid 14 moves along the linear part of the guide groove 17. The second accumulation mechanism is composed of a rotary gear 28, a torsion coil spring 29, a gear wheel 31, a pinion 32 and a rack 33 so as to store the turning force while the lid 14 moves along the arc-shaped part of the guide groove 17.
Japanese Patent Publication No. 2007-276572 discloses a storage box comprising a first guide groove 12 and a second guide groove 13. The first guide groove 12 leads the lid 2 in an anteroposterior direction of a box body 1 while the lid 2 is kept closed. The second guide groove 13 makes the lid 2 rotate together with a rotary member 4 so as to open or close the lid 2, after the lid 2 is disengaged from the first guide groove 12 and then engages with the rotary member 4 in the rear position of the box body 1. The first guide groove 12 is formed to allow a vehicle driver to adjust the position of the lid 2 to his physique, especially when the lid 2 is used as an armrest, by moving the lid 2 in an anteroposterior direction of the box body 1. However, the second guide groove 13 is formed to open and close the storage box by rotating the lid 2, only when the lid 2 is in the rear portion of the box body 1. Therefore, the feature of the first guide groove 12 can be clearly distinguished from the feature of the second guide groove 13. Since either the first guide groove 12 or the second guide groove 13 engages with the lid 2 continuously, the storage box can provide not only a useful armrest but also a storage box lid that can be rotated along a circular arc having a reduced radius when the lid is drawn backward.
However, the guide groove for controlling opening and closing movement of the lid must be formed on the sides of the box body as described in Japanese Patent Publication No. 2006-27476. In order to prevent the arm of the lid from hitting against the goods stored in the box body as the guide pin moves along the guide groove, it is needed to form such a protective side wall as described in paragraphs 0003 to 0005 of Japanese Patent Publication No. 2007-276572.
Instead of forming the foregoing protective side wall, the guide groove disclosed in Japanese Patent Publication No. 2006-27476 may be formed as a second guide groove on the outside surface of the rear side wall of the box body as described in paragraph 0032 of Japanese Patent Publication No. 2007-276572. If a bar-like projection that is formed on the transfer member is inserted into the second guide groove as described in paragraph 0037 and FIG. 8 of Japanese Patent Publication No. 2007-276572, however, it is also needed to form a space for storing the transfer member in the box body.
In other words, the existing devices disclosed in Japanese Patent Publication Nos. 2006-27476 and 2007-276572 require a guide groove to be formed on the inside surface or outside surface of the box body so as to control the direction of rotation of the lid when opening and closing the lid. Consequently, Consequently, various sorts of parts or members such as a guide pin, a bar-like projection, an arm and a transfer member must be disposed on a side surface of the box body. In addition, a space for storing the arm and the transfer member etc. must be formed on the side surface of the box body.
Furthermore, the existing devices disclosed in Japanese Patent Publication Nos. 2006-27476 and 2007-276572 are adapted to reduce the distance between a front end of the lid and a rotation axis of the lid preparatory to open the lid, by virtue of a linear part of the guide groove, which extends from an anterior end to a middle portion of the guide groove and rises gently toward the middle portion. With use of this mechanism, a vehicle driver can rotate a front end of the lid along a circular arc having a reduced radius when opening and closing the lid. When opening the lid, therefore, a closed lid must be drawn toward the back of the storage box in a predetermined distance preparatory to open the lid. When closing the lid, a closed lid may be moved toward the front of the storage box in a prescribed distance after the lid has been closed by tuning the lid around the rotation axis thereof.
In addition, the existing devices disclosed in Japanese Patent Publication Nos. 2006-27476 and 2007-276572 make the lid open and close by sliding a guide pin in a guide groove acting as a cam groove. The guide groove is composed of a liner part extending from an anterior end to a middle portion of the guide groove and rising gently toward the middle portion, a convex curve part steeply raising along a circular arc centering on a rotation axis of the lid and extending from the middle portion to a posterior portion of the groove, and a concave curve part of small diameter connecting the linear part to the convex curve part at the middle portion of the groove. The second groove of Japanese Patent Publication No. 2007-276572 corresponds to the aforementioned guide groove. Consequently, the sliding direction of the guide pin cannot help changing significantly in the concave curve part of the guide groove. In order to slide the guide pin smoothly in the concave curve part of the guide groove when closing the lid, the existing devices require means for biasing the lid in the closing direction. A force to bias the lid toward the closing direction should be a turning force centering on the rotation axis of the lid when the guide pin is sliding in the convex curve part extending from the posterior end of the groove to the middle portion of the groove, while the biasing force should be a linear force directed to the front end of the box body when the guide pin is sliding in the linear part extending from the middle portion of the groove to the anterior end of the groove. Consequently, the existing device disclosed in Japanese Patent Publication No. 2006-27476 has a first accumulation means and a second accumulation means in order to accumulate the turning force and the linear force, separately, when opening the lid. As for the device of Japanese Patent Publication No. 2007-276572, the lid is forced to rotate in the closing direction by means of a couple of springs 47, 48 and forced to move in the horizontal direction by means of one of the springs 47, 48, when closing the lid. The both devices of Japanese Patent Publication Nos. 2006-27476 and 2007-276572 have a complicated lid-closing mechanism composed of a lot of parts.